Torque Analysis in Permanent-Magnet Synchronous Motors: A Comparative Study

• Published in: IEEE transactions on energy conversion Vol. 26; no. 1; pp. 55 - 63
• Main Authors: Güemes, J A, Iraolagoitia, A A, Del Hoyo, J J, Fernández, P
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-03-2011; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Cogging torque; Construction industry; Finite element method; Finite element methods; Forging; fractional-slot windings; magnet skewing (step-skew); Magnetic analysis; Mathematical analysis; Motors; Permanent magnet motors; permanent magnet synchronous motors (PMSMs); Reduction; Reluctance motors; Ripples; Stators; Synchronous motors; Teeth; Tensors; Torque; torque ripple
• ISSN: 0885-8969; 1558-0059
• DOI: 10.1109/TEC.2010.2053374

This paper examines the torque ripple and cogging-torque variation in permanent-magnet synchronous motors (PMSMs). The effect of slot number and magnet skewing on electromagnetic motor torque, has been analyzed in different 20-pole, three-phase, PMSM configurations having the same envelop dimensions and output requirements. Finite-element technique is used for machine characteristics computation. Maxwell-stress tensor is used to find torque. Finite-element analysis results show that: 1) motors with fractional-slot winding have lower torque ripple but show a reduction of the average torque and 2) in step-skew magnet motors, torque-ripple reduction is significant only for a certain step number and magnet-skew angle.